The network device will cause the service interruption when the frame flow loss appears in the transmission process, and there are many kinds of technologies in the industry to quickly monitor the situation of flow transmission of the network. For example, according to the definition of the Operation Administration Maintenance (abbreviated as OAM), the end-to-end frame (the frame also can be called as packet or message) loss of the network is measured by adopting the on-demand frame Loss Measurement (abbreviated as LM) function.
In the OAM, on two Maintenance Entity Group (abbreviated as MEG) End Point (MEP) devices (the device is also called the node or the device node in this text) of one EMG, the source MEP sends the frame Loss Measurement Message (abbreviated as LMM) to the sink MEP (that is, the opposite end MEP), and then the sink MEP feeds back the frame Loss Measurement Response (abbreviated as LMR) to the source MEP, and the source MEP synthetically calculates the number of the lost frames and the frame loss rate from the local information and information carried in the received LMR.
When the frame loss is measured by adopting the LM function, the following several parameters need to be used:
TxFCf: the count of local transmitted frames when sending the LMM;
RxFCf: the count of local received frames when receiving the LMM;
TxFCb: the count of local transmitted frames when sending the LMR.
When the source MEP sends the LMM frame, the TxFCf is written into the LMM frame; when the sink MEP receives the LMM frame, the TxFCf of the received LMM frame is copied into the LMR, and the RxFCf and the TxFCb are written into the LMR, and then the sink MEP sends the LMR frame; when the source MEP receives the LMR frame, it records the TxFCf, the RxFCf and the TxFCb in the LMR frame and the count RxFC 1 of local received frames at the moment that the LMR frame has already been received.
If the above-mentioned count values after the source MEP receives the LMR are TxFCf [tc], RxFCf [tc], TxFCb [tc] and RxFC1 [tc] respectively, and last above-mentioned count values are TxFCf [tp], RxFCf [tp], TxFCb [tp] and RxFC1 [tp] respectively, then the count of lost frames calculated by the source MEP is as follows:
the number of lost frames from the sink MEP to the source MEP, Frame Loss [far-end]=|TxFCf[tc]−TxFCf[tp]|−IRxFCf[tc]−RxFCf[tp]|
the number of lost frames from the source MEP to the sink MEP, Frame Loss [near-end]=|TxFCb [tc]−TxFCb [tp]|−|RxFC1 [tc]−RxFC1[tp]|.
The LM function of the OAM needs the protocol cooperation of multiple devices, which can only be used for monitoring the situation of frame transmission from device to device in the network; as to the situation of the frame loss within a single device of the packet switching network (such as, the Ethernet, the internet protocol (abbreviated as IP) network, the Multi-Protocol Label Switching (abbreviated as the MPLS) network, the MPLS Transport Profile (abbreviated as the MPLS-TP) network and the Packet Transport Network (abbreviated as PTN) network, etc.), it is not applicable to the scene requiring to monitor the frame loss of the single device. FIG. 1 is a diagram of a frame loss measurement technology according to the related art. As shown in FIG. 1, the figure is a diagram of monitoring the network frame transmission by using the LM function of the OAM, and the device node S1 sends the LMM frame from the port 1 and writes the TxFCf of the port 1 of the device node S1 into the LMM frame; after the device node S5 receives the LMM frame, it copies the TxFCf of the received LMM frame into the LMR and writes the RxFCf and the TxFCb of the port 8 into the LMR, and then sends the LMR frame; the device node S1 calculates the count of the frame loss between the device nodes S1 and S5 according to the frame count and the count of the received frames of the present device node after receiving the LMR frame.
However, this method can only calculate the end-to-end count of lost frames among the devices, and cannot be used for measuring the frame loss within the single device. For example, in FIG. 1, in the path between the device nodes S1 and S5, the frame is lost within the device node S3; and the device nodes S1 and S5 can detect that there is the frame loss in the path, but it is unable to determine which device has the frame loss. In addition, the LM function of the OAM needs the protocol cooperation among multiple device nodes, and the applications are more complicated; if there are some devices in the network which do not support the function, then the function is unable to be applied by the network, so the application scene is limited, and the construction cost is higher.
And in the project application, only when quickly locating which specific device has the frame loss, it can further analyze the specific reason why the frame loss occurs in the device, and find out the basic problem. So, the project needs a more flexible and more economical and practical device transmission monitoring method.
For the problems of failing to determine a specific device where the frame loss occurs and the construction cost being high in the related technology, the effective solution has not been proposed yet at present.